CBS Antibody – Mouse Monoclonal

The protein encoded by this gene acts as a homotetramer to catalyze the conversion of homocysteine to cystathionine, the first step in the transsulfuration pathway. The encoded protein is allosterically activated by adenosyl-methionine and uses pyridoxal phosphate as a cofactor. Defects in this gene can cause cystathionine beta-synthase deficiency (CBSD), which can lead to homocystinuria. Multiple alternatively spliced transcript variants have been found for this gene. [provided by RefSeq, May 2010]

CBS: Only known pyridoxal phosphate-dependent enzyme that contains heme. Important regulator of hydrogen sulfide, especially in the brain, utilizing cysteine instead of serine to catalyze the formation of hydrogen sulfide. Hydrogen sulfide is a gastratransmitter with signaling and cytoprotective effects such as acting as a neuromodulator in the brain to protect neurons against hypoxic injury. Defects in CBS are the cause of cystathionine beta- synthase deficiency (CBSD). CBSD is an enzymatic deficiency resulting in altered sulfur metabolism and homocystinuria. The clinical features of untreated homocystinuria due to CBS deficiency include myopia, ectopia lentis, mental retardation, skeletal anomalies resembling Marfan syndrome, and thromboembolic events. Light skin and hair can also be present. Biochemical features include increased urinary homocystine and methionine. Belongs to the cysteine synthase/cystathionine beta- synthase family. 2 isoforms of the human protein are produced by alternative splicing.

Protein type: Lyase; Amino Acid Metabolism - glycine, serine and threonine; EC 4.2.1.22; Amino Acid Metabolism - cysteine and methionine; Other Amino Acids Metabolism - selenoamino acid

Chromosomal Location of Human Ortholog: 21q22.3

Cellular Component: intracellular membrane-bound organelle; nucleolus; nucleus; cytosol

Molecular Function: identical protein binding; protein binding; enzyme binding; protein homodimerization activity; cystathionine beta-synthase activity; ubiquitin protein ligase binding; metal ion binding; heme binding; pyridoxal phosphate binding

Biological Process: cysteine biosynthetic process via cystathionine; homocysteine catabolic process; L-serine metabolic process; sulfur amino acid metabolic process; transsulfuration; cysteine biosynthetic process from serine; homocysteine metabolic process; L-serine catabolic process; L-cysteine catabolic process

Disease: Homocystinuria Due To Cystathionine Beta-synthase Deficiency